The present invention relates to thin free standing single crystal silicon films, and more particularly to a novel method of making such films.
Free standing single crystal semiconductor films have come to be employed in an enormous number of electronic and related applications, most particularly in the fabrication of electronic devices such as: transistors, sensors and the like.
Presently, semiconductor substrates are sawn from a cylindrical single crystal material (boule) to produce a disk shaped substrate (wafer or slice). Since the sawing action involves a grinding away of the substrate by the saw, an amount of the substrate equal to the width of the saw will be ground away and lost, this loss generally being referred to as "kerf loss".
In producing very thin films it is not unlikely that the kerf loss for each film may be equal to or even greater than the amount of material which ultimately remains in the film. This involves a substantial loss, since the original wafer or substrate represents a very expensive starting material. As a result, the material cost of producing thin films is inordinately high, and in addition, sawing techniques are generally limited to the production of films having a minimum thickness of about several hundred microns.